I need to grab the linux shell {command} into ruby

Question

I cannot get the linux current users, memory, hdd usage, cpu load into ruby.

require 'socket'
puts "\n"

time = Time.new   
#puts time.day, time.month, time.year
puts "Date " + time.strftime("%d/%m/%Y")+"\t\t\tTime " + time.strftime("%H:%M:%S")+"\t\t\tSystem-Name: " + Socket.gethostname
puts "----------------------------------------------------------------------------------------------"
puts "Uptime: " 

#Uptime
uptime = exec "uptime"

#Memory Usage

system (free -m | awk 'NR==2{printf "Memory Usage: %s/%sMB (%.2f%%)\n", $3,$2,$3*100/$2 }')

#Disk usage
df -h | awk '$NF=="/"{printf "Disk Usage: %d/%dGB (%s)\n", $3,$2,$5}'

#Current Users
users | awk '{for(i=1;i<=NF;i++) {a[$i]++}} END {for(i in a) {print "Current Users:\t"a[i]}}'

#CPU load
top -bn1 | grep load | awk '{printf "CPU Load: %.2f\n", $(NF-2)}'

Please format your questions better in the future. – Amadan Oct 03 '16 at 07:01 — Amadan, Oct 03 '16 at 07:01

score 2 · Answer 1 · edited May 23 '17 at 10:27

2

Use backticks

`command`

instead of exec or system.

You might want to read this answer about the different ways to run system commands and about their differences.

edited May 23 '17 at 10:27

Community

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answered Oct 03 '16 at 07:02

spickermann

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Isn't this working? \`(free -m | awk 'NR==2{printf "Memory Usage: %s/%sMB (%.2f%%)\n", $3,$2,$3*100/$2 }')\` Not the surrounding backticks. What error do you get? – spickermann Oct 03 '16 at 08:29
What do you mean by *doesnt work*? Is there an error message? Is something returned that doesn't meet you expectations? – spickermann Oct 03 '16 at 09:28
And what does it return instead? If you don't answer my questions, I will not able to help you... – spickermann Oct 03 '16 at 11:53
i want to get a linux memory usage into a ruby – Yeurion muveeWatcher Oct 04 '16 at 04:06

score 1 · Answer 2 · answered Oct 03 '16 at 07:01

1

To grab the stdout and stderr from external commands, you can't use exec or system, but have to do it like this:

 output = `command`

answered Oct 03 '16 at 07:01

user1934428

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score 0 · Answer 3 · answered Oct 03 '16 at 07:12

0

First: option should work better, because it returns in the string format.

Second: option is good for some reasons like clear the logs.

1) uptime = `uptime`
#OR
2) system("clear")

answered Oct 03 '16 at 07:12

7urkm3n

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using awk in ruby ? – Yeurion muveeWatcher Oct 03 '16 at 08:11
@YeurionmuveeWatcher http://stackoverflow.com/questions/7220896/get-current-ruby-process-memory-usage and http://www.be9.io/2015/09/21/memory-leak/ – 7urkm3n Oct 03 '16 at 16:56

I need to grab the linux shell {command} into ruby

3 Answers3